This project will investigate the chemistry of molybdenum compounds which have potential relevance to understanding molybdenum in enzymes. Special emphasis will be given to the definitive establishment of the composition and structure of compounds by x-ray crystallography. Particular attention will be directed toward compounds with sulfur donor atoms which exhibit oxidation-reduction reactions and to monomeric compounds of Mo(III) and Mo(V). BIBLIOGRAPHIC REFERENCES: J. I. Gelder and J. H. Enemark, "Crystal and Molecular Structure of Tetra-n-butylammonium Di-micro-sulfidobis(oxo-1,1-dicyanoethylene-2,2-dithiolatomolybdenum (V), ((n-C4H9)4N)2(Mo2O2S2(S2C2(CN)2)2)", Inorg. Chem., 15, 1839 (1976). K. Yamanouchi, J. H. Enemark, J.W. McDonald and W.E. Newton, "A Triply Bridged Binuclear Mo(V) Compound Containing Two Kinds of Bridging Thiophenolate Groups", J. Am. Chem. Soc., 1977, in press.